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It has a watershed area of approximately 32 square miles, encompassing parts of six municipalities. The watershed is quite varied in many respects. At nearly 14 miles in length along the north-south axis, elevations range from sea level up to 630’. Because of its glacial geology, the topography includes low hills, while the main river valley features steep escarpments. The development patterns essentially divide the watershed in two: the developed southern and eastern portions of the watershed, and the rural headwaters to the north and west. Princeton Hydro was contracted by Fairfield County, CT to develop the Mill River Watershed Management Plan (WMP). The Fairfield Conservation Commission, part of the municipal government for the Town of Fairfield, applied for a Clean Water Act Section 319(h) Nonpoint Source Program grant with CT DEEP to help address the TMDL and other nonpoint source (NPS) pollutant loading and stormwater management concerns in the Mill River. The grant was awarded for the development of this Watershed Management Plan (WMP). Princeton Hydro worked with project partners, including Connecticut DEEP, Harbor Watch, Trout Unlimited, Fairfield Shellfish Commission, FairPLAN, Mill River Wetland Committee, and Lake Hills Association, throughout the watershed planning process. Mill River does not meet some of the water quality standards or designated uses. For example, in 2004 Mill River was added to the 303(d) List of Impaired Waterbodies, which is named after a section of the Clean Water Act that mandates tracking and reporting of impaired waters, for exceeding the standards associated with indicator bacteria. Mill River has had problems with excessive concentrations of Escherichia coli, more commonly E. coli. The WMP was primarily intended to provide a path to improve water quality throughout the watershed. The plan followed the requirements for the Environmental Protection Agency’s watershed-based plans (WBP) that addresses nine specific elements. This type of plan therefore covered a wide range of topics including identification of water quality problems, determining the cause of those problems, identifying measures to correct the problems, securing the technical and financial assistance to implement the plan, and developing criteria, schedules, and a monitoring program to track progress. Throughout this process, Princeton Hydro routinely met with stakeholders to define their vision and refine the plan to meet the goals and objectives in an achievable manner. [gallery columns="2" link="none" size="full" ids="19552,19551"] [post_title] => Mill River Watershed Management Plan [post_excerpt] => [post_status] => publish [comment_status] => closed [ping_status] => closed [post_password] => [post_name] => mill-river-watershed-management-plan [to_ping] => [pinged] => [post_modified] => 2026-04-07 18:21:59 [post_modified_gmt] => 2026-04-07 18:21:59 [post_content_filtered] => [post_parent] => 0 [guid] => https://princetonhydro.com/?post_type=project&p=19550 [menu_order] => 0 [post_type] => project [post_mime_type] => [comment_count] => 0 [filter] => raw ) [1] => WP_Post Object ( [ID] => 19292 [post_author] => 1 [post_date] => 2026-03-06 13:46:46 [post_date_gmt] => 2026-03-06 13:46:46 [post_content] => The Goethals Bridge Replacement Project resulted in unavoidable impacts to 4.929 acres of wetlands and open water associated with the Arthur Kill, requiring the creation of 15.39 acres of mudflat, low marsh, high marsh, and scrub/shrub habitat; and preservation of 3.91 acres of existing low marsh/high marsh and open water habitat. Princeton Hydro worked with the United States Army Corps of Engineers (USACE) – New York District and the New York State Department of Environmental Conservation (NYSDEC) on the development of an acceptable monitoring program that was implemented in 2019. As stipulated in the NYSDEC-issued permit, the monitoring program had to follow the New York State Salt Marsh Restoration and Monitoring Guidelines (Guidelines) established in 2000. Working closely with USACE and NYSDEC and following the program specified within the Guidelines, Princeton Hydro established five transects and eighteen associated 1m2 quadrat locations along the five transects. Each transect represented a cross section of the various ecological communities present between Old Place Creek and the upper extent of the mitigation site. The ecological communities monitored across each transect included low marsh, high marsh, transitional zones between low marsh and high marsh, and scrub/shrub, respectively. [gallery link="none" columns="2" ids="19307,19305"] The following metrics were calculated within each 1m2 quadrat: overall percent cover and species composition comprising the observed percent cover. Within each 1m2 quadrat, a 0.25m2 portion of the quadrat was analyzed for stem density and plant height as outlined within the Guidelines. Additionally, the entire mitigation site was investigated for the presence of invasive species with subsequent mapping developed and incorporated into an adaptive management plan. This was then implemented to address the presence of common reed (Phragmites australis). Annual monitoring reports were prepared and submitted to both USACE and NYSDEC detailing the results of the monitoring effort with a focus on the established transects and 1m2 quadrats along each transect. A section of the reports was dedicated to the development of an adaptive management plan to ensure the mitigation site satisfied the requisite 85% vegetative cover comprised of desirable, native species. [post_title] => NYSDEC Wetland Monitoring - Old Place Creek Mitigation Site [post_excerpt] => [post_status] => publish [comment_status] => closed [ping_status] => closed [post_password] => [post_name] => nysdec-wetland-monitoring-old-place-creek-mitigation-site [to_ping] => [pinged] => [post_modified] => 2026-03-06 13:46:46 [post_modified_gmt] => 2026-03-06 13:46:46 [post_content_filtered] => [post_parent] => 0 [guid] => https://princetonhydro.com/?post_type=project&p=19292 [menu_order] => 0 [post_type] => project [post_mime_type] => [comment_count] => 0 [filter] => raw ) [2] => WP_Post Object ( [ID] => 19291 [post_author] => 1 [post_date] => 2026-03-06 13:38:57 [post_date_gmt] => 2026-03-06 13:38:57 [post_content] => In response to recurring water quality issues, including a significant cyanobacterial bloom in 2014 that led to prolonged beach closures, the Town of Putnam Valley engaged Princeton Hydro to revise and update the Lake Peekskill Watershed Management Plan. The lake, a small impoundment of Peekskill Hollow Creek, serves as a vital recreational resource for the community. Princeton Hydro’s initial study was structured around three core tasks: (1) analysis of long-term water quality data, (2) development of an updated pollutant budget, and (3) formulation of short- and long-term management strategies. The analysis revealed a steady increase in conductivity and total phosphorus (TP) concentrations over the past two decades, indicating rising nutrient loads and a shift toward eutrophic conditions. Elevated TP levels were directly linked to increased algal biomass, particularly harmful cyanobacteria producing microcystin-LR, which exceeded safe swimming thresholds in 2014. The updated pollutant budget identified septic system leachate (55%) and stormwater runoff (22%) as the primary sources of phosphorus entering the lake. Internal loading from sediments and atmospheric deposition also contributed to the nutrient burden. To address these issues, Princeton Hydro proposed a suite of in-lake management interventions focused on the lake’s three public beaches. Recommendations included installing electric water pumps to improve circulation at Carrara’s Beach and ozone/aeration systems at Singer’s and North Beaches to reduce organic buildup and mitigate algal blooms. These nature-based, non-chemical solutions were designed to provide immediate relief while longer-term watershed improvements, such as septic upgrades and stormwater controls, are pursued. The plan emphasized the need for community engagement, regulatory coordination, and sustainable implementation to restore and protect Lake Peekskill’s ecological health and recreational value. Building on this foundational work, Princeton Hydro was re-engaged in 2022 by the Lake Peekskill Civic Association (LPCA) and the Town of Putnam Valley to provide additional lake management services. The team developed a comprehensive Lake Management Plan aimed at identifying and prioritizing cost-effective green infrastructure and stormwater Best Management Practices (BMPs) for implementation by the Town. The goal was to reduce nutrient loading, improve water quality, mitigate nuisance aquatic vegetation, prevent harmful algal blooms (HABs), and enhance overall stormwater management within the watershed. This phase of work included a detailed analysis of historical water quality data, a submerged aquatic macrophyte survey, and a field-based water quality assessment. Princeton Hydro also conducted a pollutant removal analysis to evaluate the effectiveness of specific watershed-based management techniques. The resulting plan provided a clear roadmap for reducing annual pollutant loads and minimizing the occurrence and severity of HABs through targeted, science-based interventions. The recommendations were designed to be actionable, scalable, and aligned with the Town’s capacity and resources, reinforcing the long-term commitment to restoring and maintaining the health of Lake Peekskill. [post_title] => Lake Peekskill Watershed Management Planning [post_excerpt] => [post_status] => publish [comment_status] => closed [ping_status] => closed [post_password] => [post_name] => lake-peekskill-watershed-management-planning [to_ping] => [pinged] => [post_modified] => 2026-03-06 13:38:57 [post_modified_gmt] => 2026-03-06 13:38:57 [post_content_filtered] => [post_parent] => 0 [guid] => https://princetonhydro.com/?post_type=project&p=19291 [menu_order] => 0 [post_type] => project [post_mime_type] => [comment_count] => 0 [filter] => raw ) [3] => WP_Post Object ( [ID] => 19281 [post_author] => 1 [post_date] => 2026-02-05 19:57:58 [post_date_gmt] => 2026-02-05 19:57:58 [post_content] => The U.S. Army Corps of Engineers, New York District (USACE), in partnership with the New Jersey Department of Environmental Protection (NJDEP), conducted a comprehensive study to identify ecosystem restoration and flood-damage-reduction solutions for the Millstone River Basin in New Jersey. Project stakeholders included the U.S. Geological Survey, the USDA Natural Resources Conservation Service, Mercer and Middlesex Counties, Princeton University, and the Stony Brook–Millstone Watershed Association. During the study, Carnegie Lake, a freshwater impoundment of the Millstone River located in Mercer and Middlesex Counties, was identified as a significant natural resource within the watershed. As the project’s lead agency, USACE contracted Princeton Hydro to develop a detailed lake and watershed restoration plan for Carnegie Lake. The Carnegie Lake and Watershed Restoration Plan focused on three primary objectives. First, it involved collecting a wide range of site‑specific in‑lake and watershed data. Second, it quantified the hydrologic and non‑point‑source pollutant budgets for the lake, including total suspended solids and the nutrients nitrogen and phosphorus. Third, it used the findings from the first two objectives to develop a comprehensive lake and watershed restoration plan. The first objective was completed in 2003, during which extensive data were collected throughout the growing season. A major component of this effort was a detailed bathymetric survey that measured water depths and the volume of unconsolidated sediments. Additional tasks included collecting physical, chemical, and biological in‑lake data; conducting macrophyte and fisheries surveys; and collecting and analyzing baseline and stormwater samples. Hydrologic and pollutant budgets for Carnegie Lake and its watershed were then developed using standardized and widely accepted models calibrated with the collected baseline and stormwater data. These budgets informed water‑quality models used to predict in‑lake conditions under various climatic and pollutant‑loading scenarios. All water‑quality and watershed data, along with model results, were used to evaluate and prioritize feasible, cost‑effective in‑lake and watershed management techniques aimed at improving water quality and reducing pollutant loads. The project was finalized in March 2005. [gallery link="none" ids="19279,19277,19276"] [post_title] => Carnegie Lake Phase I Lake and Watershed Restoration Plan [post_excerpt] => [post_status] => publish [comment_status] => closed [ping_status] => closed [post_password] => [post_name] => carnegie-lake-phase-i-lake-and-watershed-restoration-plan [to_ping] => [pinged] => [post_modified] => 2026-04-08 16:26:56 [post_modified_gmt] => 2026-04-08 16:26:56 [post_content_filtered] => [post_parent] => 0 [guid] => https://princetonhydro.com/?post_type=project&p=19281 [menu_order] => 0 [post_type] => project [post_mime_type] => [comment_count] => 0 [filter] => raw ) [4] => WP_Post Object ( [ID] => 19075 [post_author] => 1 [post_date] => 2026-01-25 03:46:18 [post_date_gmt] => 2026-01-25 03:46:18 [post_content] => In 2007, the NJ Department of Environmental Protection (NJDEP) approved Union Township as the Lead Planning Agency for the creation of the Sidney Brook Watershed Protection Plan (WPP), with Princeton Hydro as the subcontractor. The project partners include: Union and Franklin Townships, Hunterdon County, New Jersey Water Supply Authority (NJWSA), and NJDEP. The project was funded under the Clean Water Act 319(h) program. WWPs are critical planning documents that outline the management of watersheds to comply with water quality standards and use designation, as well as protect resources and mitigate impairments. Sidney Brook is a Trout Maintenance Category One (C1) stream, which flows into the South Branch of the Raritan River. The 10 square mile watershed has a variety of rural and urban land uses which have contributed to degradation in stream function. Portions of this watershed lie within the Highlands Preservation area and Highlands Planning area, which affects future development. WPPs consist of two main components: an assessment of the watershed and a series of management actions. The assessment included a review of relevant GIS data, regulations, an exhaustive water quality study, fishery and other biological surveys, and pollutant and hydrology modeling. These were used to ascertain the function of the watershed. The impairments identified through the WPP process were recommended to be addressed through a series of management actions and BMPs. These actions are discussed in general terms and also through the inclusion of 40 specific project sites and project concepts forwarded by both Princeton Hydro and NJWSA. Additional implementation guidance was also provided to ensure the WPP is fully implemented. While the watershed earned its C1 status, there were also documented impairments in function, including thermal impacts, excessive nutrient loading, and erosion/ sedimentation. Implementation of the recommended projects was initiated by NJWSA with a demonstration project completed in 2012. Princeton Hydro has worked with Union Township to work to secure additional 319(h) grants to implement the installation of 15 discrete BMPs at four project sites. The WPP was key in seeking this funding. This WPP was formally approved in 2012 and at the time, was one of just 18 approved plans statewide. [post_title] => Sidney Brook Watershed Protection Plan [post_excerpt] => [post_status] => publish [comment_status] => closed [ping_status] => closed [post_password] => [post_name] => sidney-brook-watershed-protection-plan [to_ping] => [pinged] => [post_modified] => 2026-01-13 00:00:57 [post_modified_gmt] => 2026-01-13 00:00:57 [post_content_filtered] => [post_parent] => 0 [guid] => https://princetonhydro.com/?post_type=project&p=19075 [menu_order] => 0 [post_type] => project [post_mime_type] => [comment_count] => 0 [filter] => raw ) [5] => WP_Post Object ( [ID] => 19061 [post_author] => 1 [post_date] => 2026-01-12 21:50:23 [post_date_gmt] => 2026-01-12 21:50:23 [post_content] => From 2001 through 2002 Princeton Hydro collected the necessary field data such as in-situ, bathymetric, and discrete (both water and sediment), and also delineated and modeled the hydrologic and nutrient loads of the watershed for four (4) New Jersey state park lakes: Round Valley swimming area, Lake Absegami, Host Lake, and Hook Creek Lake. This data was then compiled and computed to prepare a Management Plan for each of the individual lakes. [gallery link="none" size="medium" ids="19062,19063,19064"] The plans provided specific objectives and recommendations for the short and long-term management of each Lake and its watershed. Both in-lake and watershed management techniques were provided in the plan. In-lake techniques tended to focus on symptomatic problems such as algal blooms and the accumulation of sediments, while watershed techniques tended to focus on reducing pollutant loads through the use of structural and non-structural Best Management Practices (BMPs) and Green Infrastructure (GI) techniques. The management techniques were priority ranked, with these rankings being dependent upon applicability, regulatory constraints, technical feasibility, degree of effectiveness, initial implementation costs, and operations and maintenance costs. In-lake restoration techniques were designed to improve the water quality and/or aesthetics of the waterbody by alleviating the specific impacts of pollution. Although these measures typically provide only short-term relief without controlling the source of the pollutants, they can substantially improve the aesthetics of a lake while the long-term, watershed-based management practices are being implemented. In contrast to in-lake restoration techniques, watershed-based techniques focused on the causes of eutrophication rather than the effects. Watershed techniques were not as visible as in-lake techniques and tended to take more time to produce their desired results. However, they were absolutely vital in reducing the pollutant load, as well as producing and sustaining long-term improvements in surface water quality for each of the lakes. [post_title] => New Jersey State Park - Diagnostic Feasibility Lake Studies [post_excerpt] => [post_status] => publish [comment_status] => closed [ping_status] => closed [post_password] => [post_name] => new-jersey-state-park-diagnostic-feasibility-lake-studies [to_ping] => [pinged] => [post_modified] => 2026-01-12 21:52:34 [post_modified_gmt] => 2026-01-12 21:52:34 [post_content_filtered] => [post_parent] => 0 [guid] => https://princetonhydro.com/?post_type=project&p=19061 [menu_order] => 0 [post_type] => project [post_mime_type] => [comment_count] => 0 [filter] => raw ) [6] => WP_Post Object ( [ID] => 18800 [post_author] => 1 [post_date] => 2025-12-02 20:22:29 [post_date_gmt] => 2025-12-02 20:22:29 [post_content] => The New Jersey Department of Military and Veteran Affairs (NJDMAVA) retained Princeton Hydro to implement ecological services at the Sea Girt National Guard Training Center in the Borough of Sea Girt, Monmouth County, New Jersey. To facilitate portions of the 2025-2029 Integrated Natural Resources Management Plan (INRMP), Princeton Hydro conducted a series of tasks such as delineating the extent of the northern and southern dune protection areas, where suitable habitat for the federally threatened, state endangered piping plover (Charadrius melodus) is present and confirming the extent of wetlands associated with a prior Letter of Interpretation. The project team also conducted an ecological assessment of the existing ecological communities with a focus on identifying the presence/extent/type of invasive species present to inform future targeted habitat management efforts identified within the INRMP and procured, on behalf of NJDMAVA, a Letter of Interpretation – Line Verification, Freshwater Wetlands General Permit 16 – Creation, restoration, and enhancement of habitat and water quality functions and values, and Coastal Zone Management General Permit 24 – Habitat creation, restoration, enhancement, and living shoreline activities. [gallery link="none" columns="2" size="large" ids="18801,18803"] [post_title] => Sea Girt Nation Guard Training Center Habitat Enhancement Project [post_excerpt] => [post_status] => publish [comment_status] => closed [ping_status] => closed [post_password] => [post_name] => sea-girt-nation-guard-training-center-habitat-enhancement-project [to_ping] => [pinged] => [post_modified] => 2025-12-08 21:44:33 [post_modified_gmt] => 2025-12-08 21:44:33 [post_content_filtered] => [post_parent] => 0 [guid] => https://princetonhydro.com/?post_type=project&p=18800 [menu_order] => 0 [post_type] => project [post_mime_type] => [comment_count] => 0 [filter] => raw ) [7] => WP_Post Object ( [ID] => 18610 [post_author] => 1 [post_date] => 2025-11-05 14:49:39 [post_date_gmt] => 2025-11-05 14:49:39 [post_content] => The Anchor QEA–Princeton Hydro team was selected by Audubon New York (and its partners Save the Sound and New York State Parks) to design the restoration and enhancement of an approximately 400-acre tidal marsh on the north-central coast of Long Island. The marsh has experienced restricted tidal flow since an earthen berm was breached in 2012 during Superstorm Sandy. The restricted tidal flow led to marsh degradation, which converted portions of the former salt marsh to brackish and freshwater marsh. The lack of tidal flushing also enabled invasive Phragmites australis to establish and spread within the marsh system. Design goals included:
The Mill River Watershed is located in Fairfield County in southwestern Connecticut. It has a watershed area of approximately 32 square miles, encompassing parts of six municipalities. The watershed is quite varied in many respects. At nearly 14 miles in length along the north-south axis, elevations range from sea level up to 630’. Because of its glacial geology, the topography includes low hills, while the main river valley features steep escarpments. The development patterns essentially divide the watershed in two: the developed southern and eastern portions of the watershed, and the rural headwaters to the north and west.
Princeton Hydro was contracted by Fairfield County, CT to develop the Mill River Watershed Management Plan (WMP). The Fairfield Conservation Commission, part of the municipal government for the Town of Fairfield, applied for a Clean Water Act Section 319(h) Nonpoint Source Program grant with CT DEEP to help address the TMDL and other nonpoint source (NPS) pollutant loading and stormwater management concerns in the Mill River. The grant was awarded for the development of this Watershed Management Plan (WMP). Princeton Hydro worked with project partners, including Connecticut DEEP, Harbor Watch, Trout Unlimited, Fairfield Shellfish Commission, FairPLAN, Mill River Wetland Committee, and Lake Hills Association, throughout the watershed planning process.
Mill River does not meet some of the water quality standards or designated uses. For example, in 2004 Mill River was added to the 303(d) List of Impaired Waterbodies, which is named after a section of the Clean Water Act that mandates tracking and reporting of impaired waters, for exceeding the standards associated with indicator bacteria. Mill River has had problems with excessive concentrations of Escherichia coli, more commonly E. coli.
The WMP was primarily intended to provide a path to improve water quality throughout the watershed. The plan followed the requirements for the Environmental Protection Agency’s watershed-based plans (WBP) that addresses nine specific elements. This type of plan therefore covered a wide range of topics including identification of water quality problems, determining the cause of those problems, identifying measures to correct the problems, securing the technical and financial assistance to implement the plan, and developing criteria, schedules, and a monitoring program to track progress. Throughout this process, Princeton Hydro routinely met with stakeholders to define their vision and refine the plan to meet the goals and objectives in an achievable manner.
The Goethals Bridge Replacement Project resulted in unavoidable impacts to 4.929 acres of wetlands and open water associated with the Arthur Kill, requiring the creation of 15.39 acres of mudflat, low marsh, high marsh, and scrub/shrub habitat; and preservation of 3.91 acres of existing low marsh/high marsh and open water habitat. Princeton Hydro worked with the United States Army Corps of Engineers (USACE) – New York District and the New York State Department of Environmental Conservation (NYSDEC) on the development of an acceptable monitoring program that was implemented in 2019. As stipulated in the NYSDEC-issued permit, the monitoring program had to follow the New York State Salt Marsh Restoration and Monitoring Guidelines (Guidelines) established in 2000. Working closely with USACE and NYSDEC and following the program specified within the Guidelines, Princeton Hydro established five transects and eighteen associated 1m2 quadrat locations along the five transects. Each transect represented a cross section of the various ecological communities present between Old Place Creek and the upper extent of the mitigation site. The ecological communities monitored across each transect included low marsh, high marsh, transitional zones between low marsh and high marsh, and scrub/shrub, respectively.
The following metrics were calculated within each 1m2 quadrat: overall percent cover and species composition comprising the observed percent cover. Within each 1m2 quadrat, a 0.25m2 portion of the quadrat was analyzed for stem density and plant height as outlined within the Guidelines. Additionally, the entire mitigation site was investigated for the presence of invasive species with subsequent mapping developed and incorporated into an adaptive management plan. This was then implemented to address the presence of common reed (Phragmites australis). Annual monitoring reports were prepared and submitted to both USACE and NYSDEC detailing the results of the monitoring effort with a focus on the established transects and 1m2 quadrats along each transect. A section of the reports was dedicated to the development of an adaptive management plan to ensure the mitigation site satisfied the requisite 85% vegetative cover comprised of desirable, native species.
In response to recurring water quality issues, including a significant cyanobacterial bloom in 2014 that led to prolonged beach closures, the Town of Putnam Valley engaged Princeton Hydro to revise and update the Lake Peekskill Watershed Management Plan. The lake, a small impoundment of Peekskill Hollow Creek, serves as a vital recreational resource for the community. Princeton Hydro’s initial study was structured around three core tasks: (1) analysis of long-term water quality data, (2) development of an updated pollutant budget, and (3) formulation of short- and long-term management strategies.
The analysis revealed a steady increase in conductivity and total phosphorus (TP) concentrations over the past two decades, indicating rising nutrient loads and a shift toward eutrophic conditions. Elevated TP levels were directly linked to increased algal biomass, particularly harmful cyanobacteria producing microcystin-LR, which exceeded safe swimming thresholds in 2014. The updated pollutant budget identified septic system leachate (55%) and stormwater runoff (22%) as the primary sources of phosphorus entering the lake. Internal loading from sediments and atmospheric deposition also contributed to the nutrient burden.
To address these issues, Princeton Hydro proposed a suite of in-lake management interventions focused on the lake’s three public beaches. Recommendations included installing electric water pumps to improve circulation at Carrara’s Beach and ozone/aeration systems at Singer’s and North Beaches to reduce organic buildup and mitigate algal blooms. These nature-based, non-chemical solutions were designed to provide immediate relief while longer-term watershed improvements, such as septic upgrades and stormwater controls, are pursued. The plan emphasized the need for community engagement, regulatory coordination, and sustainable implementation to restore and protect Lake Peekskill’s ecological health and recreational value.
Building on this foundational work, Princeton Hydro was re-engaged in 2022 by the Lake Peekskill Civic Association (LPCA) and the Town of Putnam Valley to provide additional lake management services. The team developed a comprehensive Lake Management Plan aimed at identifying and prioritizing cost-effective green infrastructure and stormwater Best Management Practices (BMPs) for implementation by the Town. The goal was to reduce nutrient loading, improve water quality, mitigate nuisance aquatic vegetation, prevent harmful algal blooms (HABs), and enhance overall stormwater management within the watershed.
This phase of work included a detailed analysis of historical water quality data, a submerged aquatic macrophyte survey, and a field-based water quality assessment. Princeton Hydro also conducted a pollutant removal analysis to evaluate the effectiveness of specific watershed-based management techniques. The resulting plan provided a clear roadmap for reducing annual pollutant loads and minimizing the occurrence and severity of HABs through targeted, science-based interventions. The recommendations were designed to be actionable, scalable, and aligned with the Town’s capacity and resources, reinforcing the long-term commitment to restoring and maintaining the health of Lake Peekskill.
The U.S. Army Corps of Engineers, New York District (USACE), in partnership with the New Jersey Department of Environmental Protection (NJDEP), conducted a comprehensive study to identify ecosystem restoration and flood-damage-reduction solutions for the Millstone River Basin in New Jersey. Project stakeholders included the U.S. Geological Survey, the USDA Natural Resources Conservation Service, Mercer and Middlesex Counties, Princeton University, and the Stony Brook–Millstone Watershed Association.
During the study, Carnegie Lake, a freshwater impoundment of the Millstone River located in Mercer and Middlesex Counties, was identified as a significant natural resource within the watershed. As the project’s lead agency, USACE contracted Princeton Hydro to develop a detailed lake and watershed restoration plan for Carnegie Lake.
The Carnegie Lake and Watershed Restoration Plan focused on three primary objectives. First, it involved collecting a wide range of site‑specific in‑lake and watershed data. Second, it quantified the hydrologic and non‑point‑source pollutant budgets for the lake, including total suspended solids and the nutrients nitrogen and phosphorus. Third, it used the findings from the first two objectives to develop a comprehensive lake and watershed restoration plan.
The first objective was completed in 2003, during which extensive data were collected throughout the growing season. A major component of this effort was a detailed bathymetric survey that measured water depths and the volume of unconsolidated sediments. Additional tasks included collecting physical, chemical, and biological in‑lake data; conducting macrophyte and fisheries surveys; and collecting and analyzing baseline and stormwater samples.
Hydrologic and pollutant budgets for Carnegie Lake and its watershed were then developed using standardized and widely accepted models calibrated with the collected baseline and stormwater data. These budgets informed water‑quality models used to predict in‑lake conditions under various climatic and pollutant‑loading scenarios. All water‑quality and watershed data, along with model results, were used to evaluate and prioritize feasible, cost‑effective in‑lake and watershed management techniques aimed at improving water quality and reducing pollutant loads.
The project was finalized in March 2005.
In 2007, the NJ Department of Environmental Protection (NJDEP) approved Union Township as the Lead Planning Agency for the creation of the Sidney Brook Watershed Protection Plan (WPP), with Princeton Hydro as the subcontractor. The project partners include: Union and Franklin Townships, Hunterdon County, New Jersey Water Supply Authority (NJWSA), and NJDEP. The project was funded under the Clean Water Act 319(h) program. WWPs are critical planning documents that outline the management of watersheds to comply with water quality standards and use designation, as well as protect resources and mitigate impairments.
Sidney Brook is a Trout Maintenance Category One (C1) stream, which flows into the South Branch of the Raritan River. The 10 square mile watershed has a variety of rural and urban land uses which have contributed to degradation in stream function. Portions of this watershed lie within the Highlands Preservation area and Highlands Planning area, which affects future development. WPPs consist of two main components: an assessment of the watershed and a series of management actions. The assessment included a review of relevant GIS data, regulations, an exhaustive water quality study, fishery and other biological surveys, and pollutant and hydrology modeling. These were used to ascertain the function of the watershed.
The impairments identified through the WPP process were recommended to be addressed through a series of management actions and BMPs. These actions are discussed in general terms and also through the inclusion of 40 specific project sites and project concepts forwarded by both Princeton Hydro and NJWSA. Additional implementation guidance was also provided to ensure the WPP is fully implemented.
While the watershed earned its C1 status, there were also documented impairments in function, including thermal impacts, excessive nutrient loading, and erosion/ sedimentation. Implementation of the recommended projects was initiated by NJWSA with a demonstration project completed in 2012. Princeton Hydro has worked with Union Township to work to secure additional 319(h) grants to implement the installation of 15 discrete BMPs at four project sites. The WPP was key in seeking this funding. This WPP was formally approved in 2012 and at the time, was one of just 18 approved plans statewide.
From 2001 through 2002 Princeton Hydro collected the necessary field data such as in-situ, bathymetric, and discrete (both water and sediment), and also delineated and modeled the hydrologic and nutrient loads of the watershed for four (4) New Jersey state park lakes: Round Valley swimming area, Lake Absegami, Host Lake, and Hook Creek Lake. This data was then compiled and computed to prepare a Management Plan for each of the individual lakes.
The plans provided specific objectives and recommendations for the short and long-term management of each Lake and its watershed. Both in-lake and watershed management techniques were provided in the plan. In-lake techniques tended to focus on symptomatic problems such as algal blooms and the accumulation of sediments, while watershed techniques tended to focus on reducing pollutant loads through the use of structural and non-structural Best Management Practices (BMPs) and Green Infrastructure (GI) techniques. The management techniques were priority ranked, with these rankings being dependent upon applicability, regulatory constraints, technical feasibility, degree of effectiveness, initial implementation costs, and operations and maintenance costs.
In-lake restoration techniques were designed to improve the water quality and/or aesthetics of the waterbody by alleviating the specific impacts of pollution. Although these measures typically provide only short-term relief without controlling the source of the pollutants, they can substantially improve the aesthetics of a lake while the long-term, watershed-based management practices are being implemented.
In contrast to in-lake restoration techniques, watershed-based techniques focused on the causes of eutrophication rather than the effects. Watershed techniques were not as visible as in-lake techniques and tended to take more time to produce their desired results. However, they were absolutely vital in reducing the pollutant load, as well as producing and sustaining long-term improvements in surface water quality for each of the lakes.
The New Jersey Department of Military and Veteran Affairs (NJDMAVA) retained Princeton Hydro to implement ecological services at the Sea Girt National Guard Training Center in the Borough of Sea Girt, Monmouth County, New Jersey. To facilitate portions of the 2025-2029 Integrated Natural Resources Management Plan (INRMP), Princeton Hydro conducted a series of tasks such as delineating the extent of the northern and southern dune protection areas, where suitable habitat for the federally threatened, state endangered piping plover (Charadrius melodus) is present and confirming the extent of wetlands associated with a prior Letter of Interpretation.
The project team also conducted an ecological assessment of the existing ecological communities with a focus on identifying the presence/extent/type of invasive species present to inform future targeted habitat management efforts identified within the INRMP and procured, on behalf of NJDMAVA, a Letter of Interpretation – Line Verification, Freshwater Wetlands General Permit 16 – Creation, restoration, and enhancement of habitat and water quality functions and values, and Coastal Zone Management General Permit 24 – Habitat creation, restoration, enhancement, and living shoreline activities.
The Anchor QEA–Princeton Hydro team was selected by Audubon New York (and its partners Save the Sound and New York State Parks) to design the restoration and enhancement of an approximately 400-acre tidal marsh on the north-central coast of Long Island. The marsh has experienced restricted tidal flow since an earthen berm was breached in 2012 during Superstorm Sandy. The restricted tidal flow led to marsh degradation, which converted portions of the former salt marsh to brackish and freshwater marsh. The lack of tidal flushing also enabled invasive Phragmites australis to establish and spread within the marsh system.
The Anchor QEA–Princeton Hydro team developed 60% Designs, including design drawings, a cost estimate, a long-term management plan, and a QAPP. The project design includes dredging approximately 15,000 cubic yards of material from Sunken Meadow Creek and thin layer placement of dredged material onto adjacent marsh cells to develop low and high marsh footprints; treating approximately 20 acres of Phragmites australis and phased replanting the areas with native species; creating approximately 2,000 linear feet of channels in the marsh and improving approximately 8,500 linear feet of existing channels to enhance drainage and tidal flushing; creating tidal pools and installing anchored rootwads to promote habitat diversity; modifying existing culverts within the primary flow channel through the marsh; and planting within the high and low salt marsh footprints.
The Ousatonic Fish and Game Protective Association, Inc., in partnership with the Connecticut Department of Energy and Environmental Protection’s Inland Fisheries Division, sought to remove the Papermill Pond Dam on the East Aspetuck River to restore fish habitat formerly exceptional in quality for trout, facilitate fish passage through the site, and improve accessibility and functionality for people to engage in outdoor activities at the site in order to foster deeper stewardship ethic for the watershed.
The Papermill Pond Dam, located in New Milford, is an embankment dam situated on the East Aspetuck River. It is located 2.9 miles upstream of the confluence with the Housatonic River and is the first barrier on the East Aspetuck River. The spillway is concrete capped with masonry core. It has an approximate structural height of 11 feet and length of 75 feet.
The following alternatives were analyzed: 1) no action; 2) fishway bypass channel around dam; 3) technical fishway at dam; 4) dam lowering with fishway at dam; 5) river bypass and off-line pond; and, 6) full removal. Conceptual designs were developed for each alternative. Each alternative was analyzed and rated numerically relative to twelve categories: river morphology, aquatic resources (fisheries, macroinvertebrates, water quality), recreation, historic resources, flooding, relative liability, relative short-term costs, relative long-term costs, availability of funds, and anticipated permitability. Dam removal ranked as the most feasible alternative, but dam repair stood out as the best option for maintaining the existing ease of recreational access. That alternative necessitated dam repair, ongoing maintenance and inspection, both short-term and long-term sediment dredging, and construction of a fish bypass channel. The Association considered the alternatives and decided to pursue full dam removal.
Based on negotiations with CTDEEP that considered impacts to downstream habitats and other applicable regulations, the resulting recommendation was to remove a portion of the impounded sediment prior to passive release of the remaining impounded sediment, regardless of potential contamination. This minimized transitory sediment deposition in downstream habitats, thereby reducing the short-term impacts of the project. Thus, sediment proximal to the dam is proposed to be excavated and permanently deposited in upland areas onsite.
The dam was successfully removed in 2019 under supervision of CTDEEP Fisheries Division and Princeton Hydro.
The Gloucester County Solid Waste Complex (GCSWC) was required to implement a grassland bird habitat and hibernacula mitigation and maintenance plan, totaling 71.34-acres, within an undeveloped southern portion of GCSWC land (Site). This mitigation and maintenance plan was required to offset an expansion of the existing landfill into an area which presently provides suitable grassland bird habitat. In addition to the creation of grassland bird habitat, the Permit Modification also required the implementation of periodic grassland bird surveys to document the development of the grassland and to ensure that suitable grassland habitat has been created which supports breeding grassland bird species.
Princeton Hydro assessed the existing ecological communities within a portion of the undeveloped land within the GCSWC, which was being targeted for the creation of grassland bird habitat and a hibernacula mitigation and maintenance plan. This effort identified the existing ecological communities, documented plant species, provided recommendations for grassland habitat enhancement within the existing ecological communities where warranted, provided guidelines for hibernaculum creation, and provided seed mix recommendations to create quality grassland bird habitat. This report, the “Grassland Habitat Ecological Communities Analysis”, served as the basis for the habitat creation efforts on-Site.
Concomitant to the implementation of the recommended restoration measures outlined in the Grassland Habitat Ecological Communities Analysis document, Princeton Hydro developed a systematic monitoring plan for the avian species on-Site, titled “The Grassland Bird Species and Hibernacula Monitoring Plan”. In 2023, the recommended management measures were implemented, including the application of the recommended upland and wet meadow seed mixes installed within a 70-acre portion of the Site. The seed mixes were selected to include native, desirable grassland flora which are preferred by grassland nesting avifauna. In addition to the creation of grassland bird habitat, approximately 1.34-acres of wildlife hibernacula, designed by Princeton Hydro, were installed. Subsequent to habitat implementation measures, it was determined in early 2024 that the grassland seed mix had germinated successfully, and in response, the grassland bird species monitoring was initiated for the 2024 breeding season.
Results of the first monitoring of the grassland indicate that it has developed quality habitat in its initial growing season. Additionally, the created habitat was supporting a number of grassland obligate and grassland edge breeding bird species. Point count and incidental avian surveys of the Site documented the presence of grassland and grassland edge breeding birds throughout the breeding season. These species included New Jersey State Threatened Breeding Species Grasshopper Sparrow, Horned Lark, and American Kestrel, and Special Concern Breeding Species Field Sparrow, Bank Swallow, and Brown Thrasher. In addition to these species which possess a New Jersey State listing designation, a number of additional grassland obligate, open country, and grassland edge species were documented, including a rare New Jersey breeding species in Dickcissel, along with Blue Grosbeak, Indigo Bunting, Song Sparrow, Red-winged Blackbird, Orchard Oriole, and Eastern Kingbird. Confirmations of successful breeding (i.e. nests, fledged young, feeding young, etc.) were observed in many of these species, indicating that the Site is already productive for the targeted grassland avifauna.
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